When Twitter was introduced in late 2006, asking users to post a 140-character answer to the question "What are you doing?," many criticized the results as nothing more than a collection of trivial thoughts and inane ramblings. Fast-forward three years, and the number of Twitter users has grown to millions, while the content of the many posts--better known as "tweets"--has shifted from banal to informative.

Twitter users now cover breaking news, posting links to reports, blog posts, and images. Twitter's search box also reveals what people think of the latest new gadget or movie, letting visitors eavesdrop on often spirited conversations and some insightful opinions.

Earlier this week, on The Charlie Rose Show, Google's CEO, Eric Schmidt, was asked directly whether Google might be interested in acquiring Twitter. He responded, somewhat coyly, that his company was "unlikely to buy anything right now."

Nonetheless, as Twitter grows in size and substance, it's becoming clear that it offers a unique feed of real-time conversation and sentiment. Danny Sullivan, editor of the blog Search Engine Land, compares this to the unique real-time feed of new video content offered by YouTube, which Google acquired in 2006, and says that Twitter could help improve real-time search. Notably, says Sullivan, this is something that Google isn't particularly good at. Even by scouring news sites, Google simply can't match the speed and relevancy of social sites like Digg and Twitter, he says.

Twitter's ability to capture the latest fad is evident from its "trends" feature, which reveals the most talked about topics among Twitterers. At the time this article was written, Twitter users were discussing topics including National Napping Day, DST (daylight savings time), and the new movie Watchmen. A quick search also reveals that five people within the past half hour have posted tweets about last weekend's Saturday Night Live skit called "The Rock Obama." The most recent tweet includes a link to the video and was posted just three minutes ago.

Bruce Croft, a professor of computer science at the University of Massachusetts, Amherst, says that Twitter search could perhaps help make news alerts more relevant. "If you could search or track large numbers of conversations, then there would be the possibility of developing alerts when something starts happening," he says. "And, of course, it's yet another opportunity to do massive data mining on people's activities to learn even more about what they are doing and when they are doing it."